Nuprl Lemma : in-hull-leftmost
∀g:OrientedPlane. ∀xs:{xs:Point List| geo-general-position(g;xs)} .
  (2 < ||xs||
  
⇒ (∀i,j:ℕ||xs||.
        ((¬(i = j ∈ ℤ))
        
⇒ ij ∈ Hull(xs)
        
⇒ (∃x:{k:ℕ||xs||| (¬(k = i ∈ ℤ)) ∧ (¬(k = j ∈ ℤ))} 
             ∀y:{k:ℕ||xs||| (¬(k = i ∈ ℤ)) ∧ (¬(k = j ∈ ℤ))} . ((¬(x = y ∈ ℤ)) 
⇒ (↑x L iy))))))
Proof
Definitions occuring in Statement : 
in-hull: ij ∈ Hull(xs)
, 
left-test: i L jk
, 
geo-general-position: geo-general-position(g;xs)
, 
oriented-plane: OrientedPlane
, 
geo-point: Point
, 
length: ||as||
, 
list: T List
, 
int_seg: {i..j-}
, 
assert: ↑b
, 
less_than: a < b
, 
all: ∀x:A. B[x]
, 
exists: ∃x:A. B[x]
, 
not: ¬A
, 
implies: P 
⇒ Q
, 
and: P ∧ Q
, 
set: {x:A| B[x]} 
, 
natural_number: $n
, 
int: ℤ
, 
equal: s = t ∈ T
Definitions unfolded in proof : 
all: ∀x:A. B[x]
, 
uall: ∀[x:A]. B[x]
, 
member: t ∈ T
, 
implies: P 
⇒ Q
, 
uimplies: b supposing a
, 
prop: ℙ
, 
not: ¬A
, 
subtype_rel: A ⊆r B
, 
int_seg: {i..j-}
, 
so_lambda: λ2x.t[x]
, 
so_apply: x[s]
, 
false: False
, 
guard: {T}
, 
listp: A List+
, 
or: P ∨ Q
, 
sq_type: SQType(T)
, 
uiff: uiff(P;Q)
, 
and: P ∧ Q
, 
exists: ∃x:A. B[x]
, 
bnot: ¬bb
, 
ifthenelse: if b then t else f fi 
, 
btrue: tt
, 
assert: ↑b
, 
bfalse: ff
, 
band: p ∧b q
, 
iff: P 
⇐⇒ Q
, 
rev_implies: P 
⇐ Q
, 
upto: upto(n)
, 
from-upto: [n, m)
, 
lt_int: i <z j
, 
top: Top
, 
less_than: a < b
, 
squash: ↓T
, 
less_than': less_than'(a;b)
, 
cons: [a / b]
, 
nat_plus: ℕ+
, 
nat: ℕ
, 
decidable: Dec(P)
, 
satisfiable_int_formula: satisfiable_int_formula(fmla)
, 
lelt: i ≤ j < k
, 
ge: i ≥ j 
, 
le: A ≤ B
, 
bool: 𝔹
, 
unit: Unit
, 
it: ⋅
, 
nequal: a ≠ b ∈ T 
, 
cand: A c∧ B
, 
sq_stable: SqStable(P)
, 
comparison: comparison(T)
, 
hull-cmp: hull-cmp(g;xs;i;j)
, 
true: True
Lemmas referenced : 
hull-cmp_wf, 
in-hull_wf, 
istype-int, 
set_subtype_base, 
lelt_wf, 
length_wf, 
geo-point_wf, 
int_subtype_base, 
istype-void, 
int_seg_wf, 
istype-less_than, 
list_wf, 
euclidean-plane-structure-subtype, 
euclidean-plane-subtype, 
oriented-plane-subtype, 
subtype_rel_transitivity, 
oriented-plane_wf, 
euclidean-plane_wf, 
euclidean-plane-structure_wf, 
geo-primitives_wf, 
geo-general-position_wf, 
filter_type, 
bnot_wf, 
eq_int_wf, 
bool_cases, 
subtype_base_sq, 
bool_wf, 
bool_subtype_base, 
eqtt_to_assert, 
band_wf, 
btrue_wf, 
bool_cases_sqequal, 
eqff_to_assert, 
assert-bnot, 
neg_assert_of_eq_int, 
bfalse_wf, 
upto_wf, 
subtype_rel_list, 
assert_wf, 
not_wf, 
equal-wf-base, 
istype-assert, 
iff_transitivity, 
iff_weakening_uiff, 
assert_of_bnot, 
assert_of_eq_int, 
assert_of_band, 
list-cases, 
length_of_nil_lemma, 
filter_nil_lemma, 
product_subtype_list, 
length_of_cons_lemma, 
upto_decomp2, 
add_nat_plus, 
add_nat_wf, 
length_wf_nat, 
decidable__le, 
full-omega-unsat, 
intformnot_wf, 
intformle_wf, 
itermConstant_wf, 
int_formula_prop_not_lemma, 
int_formula_prop_le_lemma, 
int_term_value_constant_lemma, 
int_formula_prop_wf, 
istype-le, 
decidable__lt, 
intformless_wf, 
int_formula_prop_less_lemma, 
nat_plus_properties, 
int_seg_properties, 
add-is-int-iff, 
intformand_wf, 
itermVar_wf, 
itermAdd_wf, 
intformeq_wf, 
int_formula_prop_and_lemma, 
int_term_value_var_lemma, 
int_term_value_add_lemma, 
int_formula_prop_eq_lemma, 
false_wf, 
subtract_wf, 
non_neg_length, 
itermSubtract_wf, 
int_term_value_subtract_lemma, 
filter_cons_lemma, 
map_cons_lemma, 
filter_wf5, 
map_wf, 
l_member_wf, 
ifthenelse_wf, 
cons_wf, 
comparison-max_wf, 
set-valueall-type, 
int-valueall-type, 
left-test_wf, 
sq_stable__assert, 
l_all_iff, 
le_wf, 
member_filter, 
and_wf, 
equal_wf, 
member_upto2, 
subtype_rel_set, 
nat_wf, 
int_seg_subtype_nat, 
istype-false, 
l_member-settype
Rules used in proof : 
cut, 
introduction, 
extract_by_obid, 
sqequalSubstitution, 
sqequalTransitivity, 
computationStep, 
sqequalReflexivity, 
lambdaFormation_alt, 
hypothesis, 
sqequalHypSubstitution, 
isectElimination, 
thin, 
hypothesisEquality, 
promote_hyp, 
independent_isectElimination, 
universeIsType, 
sqequalRule, 
functionIsType, 
equalityIstype, 
applyEquality, 
intEquality, 
lambdaEquality_alt, 
natural_numberEquality, 
because_Cache, 
setElimination, 
rename, 
sqequalBase, 
equalitySymmetry, 
inhabitedIsType, 
setIsType, 
instantiate, 
dependent_set_memberEquality_alt, 
dependent_functionElimination, 
unionElimination, 
cumulativity, 
equalityTransitivity, 
independent_functionElimination, 
productElimination, 
dependent_pairFormation_alt, 
voidElimination, 
setEquality, 
productEquality, 
isect_memberEquality_alt, 
independent_pairFormation, 
baseApply, 
closedConclusion, 
baseClosed, 
productIsType, 
imageElimination, 
hypothesis_subsumption, 
addEquality, 
approximateComputation, 
applyLambdaEquality, 
pointwiseFunctionality, 
int_eqEquality, 
equalityElimination, 
imageMemberEquality
Latex:
\mforall{}g:OrientedPlane.  \mforall{}xs:\{xs:Point  List|  geo-general-position(g;xs)\}  .
    (2  <  ||xs||
    {}\mRightarrow{}  (\mforall{}i,j:\mBbbN{}||xs||.
                ((\mneg{}(i  =  j))
                {}\mRightarrow{}  ij  \mmember{}  Hull(xs)
                {}\mRightarrow{}  (\mexists{}x:\{k:\mBbbN{}||xs|||  (\mneg{}(k  =  i))  \mwedge{}  (\mneg{}(k  =  j))\} 
                          \mforall{}y:\{k:\mBbbN{}||xs|||  (\mneg{}(k  =  i))  \mwedge{}  (\mneg{}(k  =  j))\}  .  ((\mneg{}(x  =  y))  {}\mRightarrow{}  (\muparrow{}x  L  iy))))))
Date html generated:
2019_10_16-PM-01_40_38
Last ObjectModification:
2018_12_21-PM-11_02_21
Theory : euclidean!plane!geometry
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